1. Field of Invention
This invention relates to strainers mounted within a tube and more specifically to strainers held within a tube by a press fit retainer.
2. Description of the Prior Art
Strainer apparatus for insertion into a tube has long been used to filter out unwanted particles in the medium carried by the tube. The medium flows through a conventional mesh strainer element which retains the unwanted particles while allowing the medium to pass therethrough.
The strainer apparatus has been held stationary within the tube by the engagement of a stressed collar with the interior surface of the tube. This collar would be shaped as a truncated cone having an outside diameter greater than the inside diameter of the tube. The collar was constructed of a resilient material whereby the collar would be compressed for insertion into the tube. Once in the tube the collar would expand against the interior surfaces of the tube with sufficient force to hold the collar in place and to form a tight seal within the tube. The strainer element would be affixed to the collar in such a manner that the medium flowing through the tube would pass through the center of the collar and through the strainer element.
This type of strainer apparatus although efficient, economical and easy to assemble has proved unacceptable for tubes having a small inside diameter. With a small inside diameter the collar tends to crimp and fold over upon itself during compression upon insertion. Furthermore, once the collar crimps or folds over, it is no longer capable of making a tight seal with the interior surface of the tube. Without a tight seal, there may be insufficient force exerted by the collar to hold the strainer apparatus stationary. Also, as a result of the crimping of the collar, unwanted particles may avoid being captured in the strainer element by passing through spaces between the interior tube surface and the collar.